How To Perform The Close Grip Bench Press
You can either be flat footed or just have toes on the ground. Either way, push your toes to generate some tension in your quads. Generating tension through your whole body will help you lift more weight.
Point your rib cage at the ceiling and pull your shoulder blades back really hard. Dig your shoulder blades into the bench. This will arch your spine somewhat. This is the only time it is ok to extend your spine. Because you are braced against the bench, the bench will soak up a lot of the tension that would otherwise fall on your lumbar spine.
Grip width should be exactly shoulder width. Bringing your hands closer than shoulder width will not increase the range of motion at your elbows (the joint the triceps act on). And going any closer than shoulder width tends to only put more stress on your wrist and shoulder joints. If you are not sure what a shoulder width grip is, simply point both of your arms straight out in front of you. You can also lay on the bench and do this. Use the markings on the bar to make sure your hands are even as well.
Make sure the bar is set very deeply in your hands. This will help keep your wrists in a strong neutral position. Also, this will prevent your wrists from getting extended.
Performing The close Grip Bench Press
After you have un-racked the bar, you will initiate the rep by breaking at the elbows. Took your elbows very hard into your side. The bar should land lower on your torso than it does with a normal bench press. As you tap your torso with the bar begin to press the bar back up toward the ceiling in a J shaped arc. Make sure to extend (but not hyperextend) your elbows at the top of each rep.